Phenylindolylmethyldiaminopyrimidines (PIDAPs) as Potent Antimicrobials Against Staphylococcus Aureus

We have ascertained that phenylindolylmethyldiaminopyrimidines (PIDAPs), stop the growth of USA300 MRSA at low micromolar concentrations. The controls, penicillin G and vancomycin, are able to stop the growth of MRSA at ~765 μM (256 μg/mL) and ~1.38 μM (2 μg/mL) respectively. We have also found out that PIDAPs are bactericidal at or close to the MIC. No activity was observed against Gram-negative pathogens. Other Gram-positive pathogens have not yet been tested. Based on a search through the ChEMBL database, PIDAPs are a novel class of chemicals with antimicrobial properties. A limited structure-function study suggests that the diaminopyrimidine is part of the pharmacophore. Unfortunately, we also detected potential dose-limiting toxicity on human cell lines. Further, detailed studies are needed.